
Sweet oranges are fruits of Citrus sinensis is the family Rutaceae, while bitter oranges (also called Seville, sour, bigarade or marmalade oranges) refer to Citrus aurantium. All oranges are hybrids between pomelo (Citrus maxima, about 25% of genes) and mandarin (Citrus reticulata, 75% of genes). Hybridization might have happened at least 2,300 years ago, or much earlier.